Get Figure

Retrieves the figure file stored in GCP for a given model.

Steps:

1. Retrieve the model (same as get_model).
2. Read the annotations property from the model.
3. If the annotations do not satisfy the figure condition, raise a 400 error.
4. If the condition is met, compute the final GCP file path.
   • If the stored GCP path is a directory, append ‘figure.png’.
   • Use the organisation_id and sanitize_gcp_bucket_name to compute the bucket name.
5. Read the file from GCP and return it as an image.